A controversial British antigravity device is to be investigated by the government's National Space Centre, according to reports. If the technology really works, it would be able to counteract the force of gravity using only electrical power, permitting the easy building of Jetsons-style flying cars or hoverships and hugely simplifying space travel

That looks interesting, especially with superconductors. I think some experiments should be made in vacuum chamber to demonstrate it.

However, this principle of asymetric capacitor has been investigated by Jean-Louis Naudin six years ago: http://jnaudin.free.fr/lifters/main.htmThe difference with Emdrive, if I understand right, is that Emdrive achieves thrust at resonance frequency, what Naudin is ignoring. That might be the reason why it is so inefficient in vacuum.

There were also talks of the Nazi party looking into it before killing all the scientists when they realised they were losing the war, this is all rumours however as we dont really completely understand what happened there. Here is a photo of "The Fly Trap" Be interesting to know of thewy really were looking into this kind of device!

EmDrive (also Relativity Drive) is the name of a spacecraft propulsion system proposed, and reportedly developed, by Roger Shawyer.

New Scientist ran a cover story on EmDrive in its 8 September 2006 issue. The device is a magnetron with a specially-shaped, fully-enclosed tapering resonator cavity whose area is greater at one end. The inventor claims that the device generates thrust even though no detectable energy leaves the device.

The inventor proposes to use it as a spacecraft propulsion system that uses no fuel (other than electricity), and no reaction mass.

Sounds like man in a sail boat, drifting in the doldrums, blowing on his sail, expecting to move the boat. It shouldn't matter what the shape of the resonator cavity, the pressure being exerted is upon itself. Like trying to move a car, whilst sitting in it , by pushing against the dashboard. Yeah, cos that'll work!

It has actually nothing to do with gravity at all. It is claimed by the inventor, that the device produces a force in one direction of the cavity, regardless of its orientation. The location of the most influential gravity well makes no difference.

Rocketeer comments:Here's my take on it. It "works" after a fashion (actually generates thrust), but not in the way that Shawyer thinks it does. It's actually a form of Asymmetric Capacitor Thruster (ACT), which generates thrust by the Biefeld-Brown effect -- charged metal surfaces ionise the surrounding air by corona discharge, and create an '"ion wind" which pushes the apparatus along. Good for the continued integrity of the laws of physics, but bad for space applications of the EmDrive, because in a vacuum it would do precisely nothing.